From 90c5a2743a7049b0fbb136d841f8dc832ac5eb3c Mon Sep 17 00:00:00 2001
From: Ricardo Pardini <ricardo@pardini.net>
Date: Sat, 8 Apr 2023 13:15:17 +0200
Subject: [PATCH] kernel: introduce new hook `pre_package_kernel_image`; show
 vmlinuz file magic before/after hook; add `-HK` hook hash to kernel artifact
 version

---
 lib/functions/artifacts/artifact-kernel.sh |  9 ++++++-
 lib/functions/compilation/kernel-debs.sh   | 31 +++++++++++++++++-----
 2 files changed, 33 insertions(+), 7 deletions(-)

diff --git a/lib/functions/artifacts/artifact-kernel.sh b/lib/functions/artifacts/artifact-kernel.sh
index 203c1d48e2..3d9d352c0b 100644
--- a/lib/functions/artifacts/artifact-kernel.sh
+++ b/lib/functions/artifacts/artifact-kernel.sh
@@ -132,6 +132,13 @@ function artifact_kernel_prepare_version() {
 	vars_config_hash="${hash_vars}"
 	declare var_config_hash_short="${vars_config_hash:0:${short_hash_size}}"
 
+	# Hash the extension hooks
+	declare -a extension_hooks_to_hash=("pre_package_kernel_image")
+	declare -a extension_hooks_hashed=("$(dump_extension_method_sources_functions "${extension_hooks_to_hash[@]}")")
+	declare hash_hooks="undetermined"
+	hash_hooks="$(echo "${extension_hooks_hashed[@]}" | sha256sum | cut -d' ' -f1)"
+	declare hash_hooks_short="${hash_hooks:0:${short_hash_size}}"
+
 	# @TODO: include the compiler version? host release?
 
 	# get the hashes of the lib/ bash sources involved...
@@ -140,7 +147,7 @@ function artifact_kernel_prepare_version() {
 	declare bash_hash="${hash_files}"
 	declare bash_hash_short="${bash_hash:0:${short_hash_size}}"
 
-	declare common_version_suffix="S${short_sha1}-D${kernel_drivers_hash_short}-P${kernel_patches_hash_short}-C${config_hash_short}H${kernel_config_modification_hash_short}-V${var_config_hash_short}-B${bash_hash_short}"
+	declare common_version_suffix="S${short_sha1}-D${kernel_drivers_hash_short}-P${kernel_patches_hash_short}-C${config_hash_short}H${kernel_config_modification_hash_short}-HK${hash_hooks_short}-V${var_config_hash_short}-B${bash_hash_short}"
 
 	# outer scope
 	if [[ "${KERNEL_SKIP_MAKEFILE_VERSION:-"no"}" == "yes" ]]; then
diff --git a/lib/functions/compilation/kernel-debs.sh b/lib/functions/compilation/kernel-debs.sh
index 912cdbba91..0cc05cfe14 100644
--- a/lib/functions/compilation/kernel-debs.sh
+++ b/lib/functions/compilation/kernel-debs.sh
@@ -171,18 +171,37 @@ function kernel_package_hook_helper() {
 function kernel_package_callback_linux_image() {
 	display_alert "linux-image deb packaging" "${package_directory}" "debug"
 
-	declare installed_image_path="boot/vmlinuz-${kernel_version_family}" # using old mkdebian terminology here.
-	declare image_name="Image"                                           # "Image" for arm64. or, "zImage" for arm, or "vmlinuz" for others.
+	# @TODO: we expect _all_ kernels to produce this, which is... not true.
+	declare kernel_pre_package_path="${tmp_kernel_install_dirs[INSTALL_PATH]}"
+	declare kernel_image_pre_package_path="${kernel_pre_package_path}/vmlinuz-${kernel_version_family}"
+	declare installed_image_path="boot/vmlinuz-${kernel_version_family}" # using old mkdebian terminology here for compatibility
+
+	display_alert "Showing contents of Kbuild produced /boot" "linux-image" "debug"
+	run_host_command_logged tree -C --du -h "${tmp_kernel_install_dirs[INSTALL_PATH]}"
+
+	display_alert "Kernel-built image filetype" "vmlinuz-${kernel_version_family}: $(file --brief "${kernel_image_pre_package_path}")" "info"
+
+	declare image_name="Image" # "Image" for arm64. or, "zImage" for arm, or "vmlinuz" for others. 'image_name' is for easy mkdebian compat
 	# If NAME_KERNEL is set (usually in arch config file), warn and use that instead.
 	if [[ -n "${NAME_KERNEL}" ]]; then
 		display_alert "NAME_KERNEL is set" "using '${NAME_KERNEL}' instead of '${image_name}'" "debug"
 		image_name="${NAME_KERNEL}"
-	else
-		display_alert "NAME_KERNEL is not set" "using default '${image_name}'" "debug"
 	fi
 
-	display_alert "Showing contents of Kbuild produced /boot" "linux-image" "debug"
-	run_host_command_logged tree -C --du -h "${tmp_kernel_install_dirs[INSTALL_PATH]}"
+	# allow hook to do stuff here. Some (legacy/vendor/weird) kernels spit out a vmlinuz that needs manual conversion to uImage, etc.
+	run_host_command_logged ls -la "${kernel_pre_package_path}" "${kernel_image_pre_package_path}"
+
+	call_extension_method "pre_package_kernel_image" <<- 'PRE_PACKAGE_KERNEL_IMAGE'
+		*fix Image/uImage/zImage before packaging kernel*
+		Some (legacy/vendor) kernels need preprocessing of the produced Image/uImage/zImage before packaging.
+		Use this hook to do that, by modifying the file in place, in `${kernel_pre_package_path}` directory.
+		The final file that will be used is stored in `${kernel_image_pre_package_path}` -- which you shouldn't change.
+	PRE_PACKAGE_KERNEL_IMAGE
+
+	display_alert "Kernel image filetype after pre_package_kernel_image" "vmlinuz-${kernel_version_family}: $(file --brief "${kernel_image_pre_package_path}")" "info"
+
+	unset kernel_pre_package_path       # be done with var after hook
+	unset kernel_image_pre_package_path # be done with var after hook
 
 	run_host_command_logged cp -rp "${tmp_kernel_install_dirs[INSTALL_PATH]}" "${package_directory}/"         # /boot stuff
 	run_host_command_logged cp -rp "${tmp_kernel_install_dirs[INSTALL_MOD_PATH]}/lib" "${package_directory}/" # so "lib" stuff sits at the root